Getting Used to a Terraformed Moon

Could the Moon be terraformed? The spelling checker does not even know the word terraforming, but in science-fiction one can read it quite often: it’s about making other planets more friendly for lifeforms from Earth by adjusting the temperature and the atmosphere. The concept of terraforming is often conntected with Mars, sometimes with Venus, but rarely with the Moon. That’s a good reason to take a look at that improbable option.

Mars and Venus

The terraforming of Mars is actually not that complicated. Simply pumping CO2 and other greenhouse gases into the atmosphere will start a runaway greenhouse effect that turns up the heat and thickens the atmosphere. On our homeworld we are already practicing, unintentionally. What may cause a disaster on Earth would be a blessing on Mars. In other words, I’m pretty sure Mars will be terraformed some day, though I fear I am born a little too early to see it happen.

Venus, in terms of size and gravity, is the most Earth-like of all the planets in the solar system, but it is much harder to handle than Mars. First the temperature has to drop a good four hundred degrees; you need a parasol of planetary proportions to do that. Then you have to import water and oxygen and actually get rid of some other substances. And finally there is another challenge: a day that lasts as long as 243 Earth days! In short: terraforming Venus is something for a rather remote future.

Artist impression of our Moon in the sky, after a (unlikely) terraforming project: a living world with seas, clouds and forests
Orbital image of a terraformed Moon

The Moon

But  our own Moon it is even more difficult to terraform than Venus. Where Mars and Venus already have an atmosphere to start with, on the Moon you really have to import everything. This can be done by sending comets from the outer regions of the solar system to the Moon and letting them impact there (and thus adding some craters to the already pockmarked landscape). But it is wise not to do so until dragging comets has become a routine job that really can’t go wrong, because the Earth is only 300,000 kilometers away and you do not want one of those comets to end up there.

Plastic bag

And an even bigger challenge: once the Moon has an atmosphere, the gravity, which is one-sixth of Earth’s gravity, is too weak to hold it. It may take a hundred thousand years, but then all the air will begone. Unless you occasionally send a new comet to replenish it. Or unless you use a very advanced solution: holding the atmosphere inside a membrane, or in other words, put in a transparent plastic bag.

Hypothetical map of Earth's terraformed Moon, with lakes, seas and jungles
A surfers paradise…

Thought experiment

To summarize: terraforming the Moon is a challenge, to put it very, very mildly. And yet the idea is interesting as a thought experiment. Whatever we do with Mars and Venus, we will not notice much of it on Earth. But the Moon has an important role in our nights.


After terraforming, the light of the Moon will be different and definitely brighter. Astronomers talk about the albedo of a celestial body, the reflectiveness. Currently the Moon has an albedo of 7%; with jungles, seas, clouds and polar caps it will probably get closer to the Earth’s albedo, about 38%. In other words: the Moon will become more than five times brighter! One may be able to read a book in its light.

In addition, with an atmosphere around it, the Moon also will become a little bit bigger. In short: a walk in the moonlight will never be the same again. But not necessarily less romantic.

Atmospheric nocturnal picture of a terraformed Moon, low above the horizon, that shines its green-yellow light on a slightly undulating water surface with a sailboat on it
Sailing in terraformed moonlight


I foresee a passionate debate between supporters and opponents of lunar terraforming. Do we have the right to play god?  Is nothing sacred anymore? Do we even have to mess with the moonlight?

I think I’m with the supporters. Because we will get something in return. A small world, roughly the same size as the Asian continent, and above all: a fascinating holiday destination. With countless crater lakes and small seas (which, perhaps with foresight, have always been called “mare” (sea) by the astronomers). With very high waves and, due to the gravitational pull of the Earth, a huge tidal difference. A surfers paradise! With trees that grow into the sky (because of the previously mentioned low gravity). And with a large, colorful lampion in the sky during the long nights: the Earth.

You may also like...

2 Responses

  1. Christopherr Walker says:

    Let Us Terraform the Moon!
    This will solve the two major problems afflicting humanity: There is no more frontier! We have no purpose! Why are these two problems the most important? People without purpose do irrational things. Alpha males need a frontier where they can make their own rules.
    Irrational things? Promoting a system which allows a few to have disgusting amounts of money and many to not have any! Irrational things? Burning carbon to profit a few billionaires while destroying the ecosphere. As long as we are trapped and powerless we will allow stupid stuff to happen. Having goals beyond selfish has allowed humanity to do great things. Bringing life to the Solar System is a goal worthy of the next centuries!

    Yes, I said centuries not millennia. Luna can support life in little more than100 years.
    Solar sails are part of the answer. With them we can reach all parts of the solar system in reasonable amounts of time. If we use ion propulsion at a constant 1.2 G then the times are even faster. We can do this stuff, if we have the will.
    Next we need to throw enough of the right mass at the moon to get it rotating and provide an atmosphere. We know that mass is available and we know how to get it to hit the moon just right. Sure, the atmosphere will only keep for a few thousand years without additional help. Given a couple of thousand years we should be able to fix that.

    We know how to do this. The engineering problems are solvable. No new science is required. Do we have the will to solve the political problems?

    Why the Moon ?
    Why do you think we are being so careful on Mars? We are seeking life as if it was the prime reason for sending spacecraft there. Humanity must have an innate moral sense when it comes to life. Despite our history of genocide we take every precaution to preserve any life that might exist on Mars. This problem does not exist on the Moon!

    Pushing Comets
    The mathematics are simple. How much inertia do we need to add to the moon to give it a 60 hour day? How much mass at what speed does that take? How long will it take to get that mass with the right composition (water ice) to the impact point. Where are the impact points (given that we do not want to change the moons orbital position)?
    Something we can do right now is find those bodies of mass and calculate the orbital changes required. Shaped nuclear charges pack a big wallop, but we want to make sure that non of the pieces impact the earth. We can start by bringing a nickel iron asteroid to the L5 point to act as a source for space based manufacturing. This manufacturing base will be required to provide the infrastructure in the most efficient manner. Even with space based manufacturing there will be a lot of traffic from the Earth to outer space.

    We are Human
    Robotic systems should assist us not replace us. Getting humans into space would be a lot simpler if we had a starting ramp. Kilimanjaro and the South American Andes are good locations at the equator. The propulsion systems for these types of launch facilities are not dependant upon fossil fuels. This is also something we can start right now and would bring jobs to the poorest regions on Earth.

Leave a Reply

Your email address will not be published. Required fields are marked *

Spam-controle: * Time limit is exhausted. Please reload CAPTCHA.